Earth
] Carl Sagan - Pale blue dot, about 3 mins., added: April 29, 2007 fFpFlKy1Pso Diary international *2007 - International Year of Planet Earth is a 2008 international observance, declared by the 60th United Nations General Assembly. The Year's activities will span the three years 2007-2009. *'April 22 2007' Earth Day Natural resources * Earth's crust contains large deposits of fossil fuels: (coal, petroleum, natural gas, methane clathrate). These deposits are used by humans both for energy production and as feedstock for chemical production. * Mineral ore bodies have been formed in Earth's crust by the action of erosion and plate tectonics. These bodies form concentrated sources for many metals and other useful elements. * Earth's biosphere produces many useful biological products for humans, including (but far from limited to) food, wood, pharmaceuticals, oxygen, and the recycling of many organic wastes. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends upon dissolved nutrients washed down from the land. Some of these resources, such as mineral fuels, are difficult to replenish on a short time scale, called non-renewable resources. The exploitation of non-renewable resources near the surface by human civilization has become a subject of significant controversy in modern environmentalism movements. Land use Humans use the Earth's land to support themselves through the production of food, energy, and building material. They also live on the land by building shelters. Human use of land is approximately: * Arable land: 13.13% * Permanent crops: 4.71% * Permanent pastures: 26% * Forests and woodland: 32% * Urban areas: 1.5% * Other: 30% (1993 est.) Irrigated land: 2,481,250 km² (1993 est.) Natural and environmental hazards Large areas are subject to extreme weather such as (tropical cyclones), hurricanes, or typhoons that dominate life in those areas. Many places are subject to earthquakes, landslides, tsunamis, volcanic eruptions, tornadoes, sinkholes, blizzards, floods, droughts, and other calamities and disasters. Many localize areas are subject to human-made pollution of the air and water, acid rain and toxic substances, loss of vegetation (overgrazing, deforestation, desertification), loss of wildlife, species extinction, soil degradation, soil depletion, erosion, and introduction of invasive species. Long-term climate alteration from enhancement of the greenhouse effect caused by the earth itself and human industrial carbon dioxide emissions is an increasing concern, the focus of intense study and debate. Human geography Earth has approximately 6,500,000,000 human inhabitants (February 24 2006 estimate). Projections indicate that the world's human population will reach seven billion in 2013 and 9.1 billion in 2050 (2005 UN estimates). Most of the growth is expected to take place in developing nations. Human population density varies widely around the world. It is estimated that only one eighth of the surface of the Earth is suitable for humans to live on — three-quarters is covered by oceans, and half of the land area is desert, high mountains or other unsuitable terrain. Gaia Gaia: n. the earth viewed as a vast self-regulating organism. -ORIGIN 1970s: coined by the Engl. scientist James Lovelock from the name of the Gk goddess Gaia. (Concise Oxford Dictionary, 10th edition) "She" needs a little help from her members occasionally, especially if some of the others are profligate. Related topics *Diary international *Global connections * Category:Place Portal Category:Gaia